[应用相关] 利用stm32自带的正交编码器检测增量式编码器流程总结（转）

void InitializeEncoder(void)

{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

  TIM_ICInitTypeDef TIM_ICInitStructure;

  /* Encoder unit connected to TIM1, 4X mode */    

  GPIO_InitTypeDef GPIO_InitStructure;

  //NVIC_InitTypeDef NVIC_InitStructure;

  /* TIM1 clock source enable */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);//使能TIM1时钟

  /* Enable GPIOA, clock */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);//使能GPIOA时钟

  GPIO_StructInit(&GPIO_InitStructure);

  /* Configure PA.06,07 as encoder input */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//PA8 PA9浮空输入

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Enable the TIM1 Update Interrupt */

  //NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQChannel;

  //NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;

  //NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = TIMx_PRE_EMPTION_PRIORITY;

  //NVIC_InitStructure.NVIC_IRQChannelSubPriority = TIMx_SUB_PRIORITY;

  //NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  //NVIC_Init(&NVIC_InitStructure);

  /* Timer configuration in Encoder mode */

  TIM_DeInit(ENCODER_TIMER);

  TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);

  TIM_TimeBaseStructure.TIM_Prescaler = 0x0;  // No prescaling //设定计数器分频系数为0，不分频

  //TIM_TimeBaseStructure.TIM_Period = (4*ENCODER_PPR)-1;  //设定计数器重装值 

  TIM_TimeBaseStructure.TIM_Period = ENCODER_TIM_PERIOD-1;

  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;//设置时钟分割 T_dts = T_ck_int 

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;   //TIM向上计数

  TIM_TimeBaseInit(ENCODER_TIMER, &TIM_TimeBaseStructure);

  TIM_EncoderInterfaceConfig(ENCODER_TIMER, TIM_EncoderMode_TI12, 

         TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);//使用编码器模式3

  TIM_ICStructInit(&TIM_ICInitStructure);

  TIM_ICInitStructure.TIM_ICFilter =ICx_FILTER;//选择输入比较滤波器

  TIM_ICInit(ENCODER_TIMER, &TIM_ICInitStructure);

  // Clear all pending interrupts

  TIM_ClearFlag(ENCODER_TIMER, TIM_FLAG_Update);//清除TIM1的更新标志位

  TIM_ITConfig(ENCODER_TIMER, TIM_IT_Update, ENABLE);

  //ENC_Clear_Speed_Buffer();

  //Reset counter

  TIM1->CNT = 0;

  //CurrentCount = TIM1->CNT;

  TIM_Cmd(ENCODER_TIMER, ENABLE);

  System.Device.Encoder.Enc_GetCount = Enc_GetCount;

}

System.Device.Encoder.Enc_GetCount = Enc_GetCount;

s16   Enc_GetCount(void)

{

    static  u16   lastCount = 0;

    u16  curCount = ENCODER_TIMER->CNT;//获取编码值

    s32 dAngle = curCount - lastCount;

    if(dAngle >= MAX_COUNT)

    {

      dAngle -= ENCODER_TIM_PERIOD;

    }

    else if(dAngle < -MAX_COUNT)

    {

      dAngle += ENCODER_TIM_PERIOD;

    }

    lastCount = curCount;

    return (s16)dAngle;

}

//20141213

#define ENCODER_TIMER   TIM1  // Encoder unit connected to TIM3

#define ENCODER_PPR           (u16)(100)   // number of pulses per revolution

#define SPEED_BUFFER_SIZE 8



#define COUNTER_RESET   (u16)0

#define ICx_FILTER      (u8) 6 // 6<-> 670nsec



#define TIMx_PRE_EMPTION_PRIORITY 1

#define TIMx_SUB_PRIORITY 0



#define ENCODER_TIM_PERIOD 0xffff//最大值预分频是65536-1

#define MAX_COUNT          10000//10000也就是1ms内不会超过10000个脉冲